4/20, also known as Weed Day, falls on Monday, April 20, and has become an unofficial holiday for many Americans. What began as a coded meeting time among five students at San Rafael High School in Marin County, California, later spread through a flyer, a magazine, and pop culture until 420 became shorthand for marijuana culture and a rallying point for activists pushing for broader legalization and federal decriminalization of weed in the U.S. and beyond.
Who Started the Code
The most widely accepted origin story traces 420 back to a group of teenagers in Marin County, California. In the early 1970s, five students at San Rafael High School would meet after extracurricular activities near a wall at school. The group, eventually called the Waldos because they met by a wall, made their official meeting time 4:20 p.m. and eventually started using 420 as code for smoking. The origin story is ordinary in the way so many acts of self-organization are ordinary: a small group making its own language, outside the official channels, and turning a school wall into a meeting point.
Dave Reddix, one of the Waldo members, later got work as a roadie for the Grateful Dead, and he told Time Magazine that the band helped to popularize the term. That path from a schoolyard code to a wider cultural reference ran through music, fandom, and the informal networks that often move faster than institutions trying to control the story.
How the Word Spread
A key moment came in December 1990, when some Oakland Deadheads distributed a flyer inviting people to smoke on April 20 at 4:20 p.m. A reporter at High Times magazine got hold of the flyer and printed it in 1991, bringing it to the attention of cannabis fans across state lines. High Times continued using 420 in later publications, solidifying its place in pop culture.
Steve Bloom, the High Times reporter who originally received the flyer, later credited the Waldos for originating the term. In a 2013 blog, he wrote that "they wanted people all over the world to get together on one day each year and collectively smoke pot at the same time. They birthed the idea of a stoner holiday, which April 20 has become." The quote captures how a small, self-made code was turned into a shared ritual without needing permission from any official authority.
The day is also used by activists and supporters to call for broader legalization and federal decriminalization of weed in the U.S. and beyond. That push runs into the familiar maze of state control, where legality depends on which jurisdiction holds the power to decide what people can do with their own bodies and plants.
What the Law Allows, and Where
The legalization of marijuana varies by state, with rules ranging from medical-only use to fully recreational. Currently, at least 24 states and D.C. have legalized recreational use, and several others are weighing changes through legislation or upcoming ballot measures. The reform track remains tied to the same political machinery that has long regulated, criminalized, and selectively permitted cannabis use in the first place.
The date April 20 is shorthand for marijuana culture, and the number 420 is often used as a colloquial reference to the plant and the act of consuming it. Over the years, theories about the origin of 420 have included police codes, hidden references in classic songs, the number of active chemicals in weed, Bob Marley’s birthday, and Bob Dylan’s song “Rainy Day Women #12 & 35,” but the most widely accepted origin story remains the one that starts with five students meeting by a wall and making their own code.
That origin matters because it shows how culture can be built from below, then circulated through informal networks, media amplification, and activist use. The official calendar may call it an unofficial holiday, but the story behind 420 is one of people creating their own language and carrying it far beyond the school wall where it began.